Study On The Relationship Between The Content Change Of Gas Composition CO₂ In Stored Grain Environment And The Occurrence Of Sitophilus Oryzae And Tribolium Castaneum

In order to elucidate the relationship between the occurrence of insect pests and the CO₂ content in stored grain environment,the change of CO₂ content in stored wheat with different moisture contents of 12%,13%,and 14% infested by different initial population densities of 0,2,5,10,20,and 30 adults of Sitophilus oryzae,Tribolium castaneum or Sitophilus oryzae and Ttribolium castaneum per kg of wheat was investigated,respectively.The results showed as follows:When Sitophilus oryzae and Tribolium castaneum with different insect densities occurred respectively in the strictly closed storage environment,the CO₂ concentration showed a significant upward trend with the increase of wheat moisture content,and finally tended to be stable in the same treatment time;for the stored wheat with the same moisture content,when the Sitophilus oryzae and Tribolium castaneum with different insect densities occurred,the concentration of CO₂ gas in the storage environment showed a significant upward trend with the increase of insect density and the extension of storage time,and finally reached a peak concentration.The concentration of CO₂ gas in the storage environment increased from the initial minimum concentration of 0.060% to the maximum value of 18.217% after 30 days of storage.When Sitophilus oryzae and Tribolium castaneum with different insect densities occurred in the general closed storage environment,the CO₂ concentration did not change regularly in the same treatment time with the increase of the moisture content of wheat;the CO₂ concentration showed an obvious rising trend with the extension of treatment time in the storage environment of wheat with the same moisture content.In the strictly closed grain storage environment,a single infection with low density Sitophilus oryzae and a mixed infection of low density Sitophilus oryzae,Tribolium castaneum with the extension of treatment time,the amount of CO₂ concentration change was large compared with the single infection of low density.Under strictly closed and general closed conditions,there was a significant linear relationship between the change of CO₂ concentration and treatment time in stored wheat with different water content and infested by different insect population density of Sitophilus oryzae and Tribolium castaneum.The same moisture,the rate of change of CO₂ gas concentration in the environment of strictly closed grain storage infecting different insect density Sitophilus oryzae and Tribolium castaneum showed an increasing trend with the increase of insect density.The rate of change of CO₂ concentration in the general closed grain environment infected with pests with treatment time was significantly greater than that of uncontaminated pests in the general closed grain storage environment with the treatment time.By analyzing the CO₂ content data of different worm populations in different tightly sealed and generally closed grain storage environments,the population density,CO₂ content and wheat moisture can be obtained.The occurrence of pests in the grain storage environment is predicted.Compared with the data of CO₂ concentration change in the environment of pests in strictly closed grain storage environment,the CO₂ concentration showed a significant upward trend with the treatment time in the general closed grain storage environment,but the change of CO₂ concentration in the closed environment was greater.Therefore,the better the air tightness,the more feasible to detect the occurrence of pests in the grain storage environment by monitoring the change of CO₂ concentration.